In the 18th century, Antoine Lavoisier demonstrated that combustion consumes oxygen; previously, many scientists had believed that combustion released phlogiston, an imaginary substance that was believed to extinguish flames.

A)consumes oxygen; previously, many scientists had believed that combustion released phlogiston, an imaginary substance that was believed to extinguish flames

B)consumed oxygen, and many scientists had previously believed that phlogiston was an imaginary substance released by combustion, which extinguished flames

C)consumes oxygen; phlogiston was previously an imaginary substance that was believed to extinguish flames and that many scientists had believed was released by combustion

D)consumed oxygen; phlogiston, an imaginary substance that extinguished flames, was believed by scientists to be released by combustion

E)consumes oxygen; previously, many scientists had believed that phlogiston was released by combustion and was an imaginary substance that was believed to extinguish flames

OA is A, but using previously and a past tense "had believed" looks redundant.

Can you let me know if this is indeed redundant?